<h3>ADMIN</h3>
<nav>
<!-- exact: 类似pathMatcher: 'full', 路由链接完全匹配到./才加上active-link类 -->
  <a routerLink="./" routerLinkActive="active-link"
     [routerLinkActiveOptions]="{ exact: true }">Dashboard</a> |
  <a routerLink="./crises" routerLinkActive="active-link">Manage Crises</a> |
  <a routerLink="./heroes" routerLinkActive="active-link">Manage Heroes</a>
</nav>
<router-outlet></router-outlet>
